A dialogue generally refers to the exchange of information. People generally use language to exchange information. Use of their voice by a person will cause the hearing sense of another person to be activated and thus information is transferred. People can also specify information on media such as paper and display device using various other means. Information is thus transferred when the sight sense of others is activated. Dialogue between people and computers or the like is very common. Computers with functions to enable such dialogue are called dialogue systems or dialogue processing systems. If the word “dialogue” is used in this patent application, it includes exchanges with computers using both the hearing and the sight senses.
In the exchange of information using language, since all required information is not necessarily included in one speech (sentence), a number of exchanges are generally required before all necessary information is acquired. In conventional dialogue systems, information is acquired using a computer led method whereby a person responds to questions asked by the computer. Therefore, the flow of the dialogue is described in advance in the system as rules. In other words, conventional dialogue systems use a flowchart model that requests the speaker to enter information using a predetermined procedure. In yet another way of looking at it, the conventional methods relate to a processing method in which the recipient of the information, that is the computer, requests the speaker to enter information.
In contrast, dialogues between people cause the recipient of the information to change the behavior in accordance with the contents of the speech by the speaker. Such dialogues are therefore different to dialogues in conventional dialogue systems. Any attempts to tackle speaker led dialogue in these conventional dialogue systems necessitates the prediction of all dialogue patterns, and therefore the predication has to be performed factorial times of conditions necessary to establish a dialogue.
In Japanese Patent Application Laid-open No. 9-62739, art such as the following is disclosed. That is, in a city office, if a citizen enters their request using natural language into a device for allocating clerks at the window, the device for allocating clerks extracts keywords from the requests entered and calculates the degrees of the relationship with clerk terminals from the keywords entered. If a clerk terminal has a relationship degree higher than that of a predetermined threshold value, the device for allocating clerks connects to that clerk terminal. On the other hand, if such a clerk terminal does not exist, a vague response saying, “We cannot find a suitable clerk. Please provide more details,” is returned to the citizen.